The world No.8 Australians will open their tournament in Salford on August 23 (9pm AEST) as they look to improve on a quarter-final showing at the last tournament in 2021.
Coach Jo Yapp named a 32-player squad on Monday, which includes 15 World Cup debutants.
Defending Super Rugby Women's champions the NSW Waratahs will be represented by 13 players, while the ACT Brumbies have eight representatives, Queensland six, with five from Western Force.
Olympic gold medal winner Caslick switched from sevens this year with the ambition of playing in her first 15-a-side World Cup, but suffered a syndesmosis injury last month that required surgery.
However, she and fellow sevens convert Tia Hinds were included, along with captain Siokapesi Palu, who missed the recent two Test matches against Wales with a foot injury.
It's unclear when the injured pair will be available to play.
Teenage sensation Waiaria Ellis, 17, could become the youngest Wallaroo to play at a World Cup after being included in the youthful squad, which has an average age of 26.
Veterans Marsters and Pomare, who both recently passed 40 Test appearances, will add some much-needed experience in their third tournament.
Uncapped Reds winger Caitlin Urwin has been included after impressing for Australia A. However, there was no room for out-of-favour Waratahs playmaker Arabella McKenzie.
Lock Annabelle Codey is set to follow in her father David Codey's footsteps in playing at a World Cup, while Katalina Amosa, the sister of Wallaby Brandon Paenga-Amosa, is one of three hookers named.
"We are very proud of the squad and the journey the players and staff have been on for the past two years to get to this point," said Yapp, who will step away from the role after the tournament."We have a very special group of people within this squad, diverse in culture and a range of ages and levels of experience in the game."A World Cup is the pinnacle event in sport, and women's rugby will showcase that in England later this month."We are ready to perform on the global stage and thank everyone who is supporting us on and off the field."The tournament is set to be the biggest-ever women's rugby event, with more than 300,000 tickets sold.
Following Samoa, the Wallaroos take on  USA on August 31 and top-ranked tournament hosts England on September 6 to complete their pool matches.
WALLAROOS SQUAD: Katalina Amosa, Bree-Anna Browne, Charlotte Caslick, Emily Chancellor, Annabelle Codey, Lori Cramer, Piper Duck, Waiaria Ellis, Ashley Fernandez, Georgina Friedrichs, Caitlyn Halse, Tia Hinds, Brianna Hoy, Asoiva Karpani, Lydia Kavoa, Kaitlan Leaney, Michaela Leonard, Ashley Marsters, Desiree Miller, Faitala Moleka, Layne Morgan, Tania Naden, Bridie O'Gorman, Siokapesi Palu, Faliki Pohiva, Trilleen Pomare, Cecilia Smith, Maya Stewart, Adiana Talakai, Tabua Tuinakauvadra, Caitlin Urwin, Samantha Wood
